抄録
A nude type magnetron gauge has been developed, which is highly simplified and small. The gauge has only a cathode which is comprised of a thin vacuum chamber containing a magnet, and magnetic pole pieces.
The characteristics of the gauge are investigated in the pressure range of 10-110-8 Pa. Current I vs pressure P in a log-log plot has good linearity. This linearity is sensitive to the distance between cathode and vacuum chamber as an anode d. In the case of a short d of 10mm, the gauge shows good linearity in a wide pressure range of 6 decades, or 10-110-6Pa, with 2 kV of voltage applied to the cathode. This pressure range is very wide compared with that of a conventional penning discharge gauge. In the case of a long d of 19.5 mm, 5 decades, or 10-110-5 Pa, at 3 or 4 kV. With increase or decrease of the applied voltage, the range of linearity will be narrowed. The optimum applied voltages are 2 kV at d-10 mm, and 34 kV at d= 19.5 mm.
It is found that the gauge shows a sudden change of several times in discharge current at a pressure Pc, when the pres-sure is decreased or increased. Pc is 10-510-6 Pa for d = 19.5 mm with an applied voltage of 1.56.0 kV, and 10-310-6 Pa for d = 10 mm with an applied voltage of 1.56.0 kV.
This gauge is very useful for application in rocket and balloon experiments, and for pressure measurement in the deep portion of a vacuum chamber.
